U.S. patent application number 11/024764 was filed with the patent office on 2005-12-15 for apparatus for controlling stiffness of anti-roll bar for vehicle.
This patent application is currently assigned to Hyundai Mobis Co., Ltd.. Invention is credited to Song, June Young.
Application Number | 20050275172 11/024764 |
Document ID | / |
Family ID | 35459732 |
Filed Date | 2005-12-15 |
United States Patent
Application |
20050275172 |
Kind Code |
A1 |
Song, June Young |
December 15, 2005 |
Apparatus for controlling stiffness of anti-roll bar for
vehicle
Abstract
An apparatus for controlling stiffness of an anti-roll bar for a
vehicle, comprising: An apparatus for controlling stiffness of an
anti-roll bar for a vehicle includes an anti-roll bar provided with
piezoelectric ceramics, the anti-roll bar interconnecting both
lower arms of a vehicle suspension system, a power converter
connected to a power supply to change an amount of electric power
and to supply the electric power to the piezoelectric ceramics of
the anti-roll bar, and a controller connected to the power
converter to calculate an amount of the electric power needed for
providing the piezoelectric ceramics with optimal stiffness based
on previously stored vehicle speed and steering angle in response
to data detected by a vehicle speed sensor and a steering angle
sensor and to control the power converter such that the calculated
electric power can be supplied to the piezoelectric ceramics.
Inventors: |
Song, June Young;
(Yongin-si, KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
Hyundai Mobis Co., Ltd.
Seoul
KR
|
Family ID: |
35459732 |
Appl. No.: |
11/024764 |
Filed: |
December 30, 2004 |
Current U.S.
Class: |
280/5.511 |
Current CPC
Class: |
B60G 21/0558 20130101;
B60G 2202/424 20130101; B60G 2800/012 20130101; B60G 17/0162
20130101 |
Class at
Publication: |
280/005.511 |
International
Class: |
B60G 021/05 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 11, 2004 |
KR |
2004-0042941 |
Claims
1. An apparatus for controlling stiffness of an anti-roll bar for a
vehicle, comprising: an anti-roll bar provided with piezoelectric
ceramics, said anti-roll bar interconnecting both lower arms of a
vehicle suspension system; a power converter connected to a power
supply to change an amount of electric power and to supply the
electric power to the piezoelectric ceramics of the anti-roll bar;
and a controller connected to the power converter to calculate an
amount of the electric power needed for providing the piezoelectric
ceramics with optimal stiffness based on previously stored vehicle
speed and steering angle in response to data detected by a vehicle
speed sensor and a steering angle sensor and to control the power
converter such that the calculated electric power can be supplied
to the piezoelectric ceramics.
2. The apparatus as claimed in claim 1, wherein the anti-roll bar
is configured such that an outer circumferential surface thereof is
enclosed by the piezoelectric ceramics.
3. The apparatus as claimed in claim 1, wherein the power converter
changes a voltage supplied to the piezoelectric ceramics.
Description
RELATED APPLICATIONS
[0001] The present disclosure relates to subject matter contained
in Korean Application No. 10-2004-0042941, filed on Jun. 11, 2004,
which is herein expressly incorporated by reference its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an apparatus for
controlling stiffness of an anti-roll bar for a vehicle, and more
particularly, to an apparatus wherein piezoelectric ceramics are
added to an anti-roll bar to allow the anti-roll bar to be
controlled to exhibit its optimum stiffness according to vehicle
conditions including vehicle speed and steering angle such that the
driving stability and product value of vehicle can be
maximized.
[0004] 2. Description of the Background Art
[0005] In general, an anti-roll bar for a vehicle is a major
element of the vehicle suspension system and is called a
stabilizer. The anti-roll bar is configured to allow a central
portion of a steel rod bent into a general `` shape to function as
a torsion bar, and serves to cause no additional action when right
and left wheels are simultaneously moved in a vertical direction
and to increase its torsional stiffness due to its twisting
operation when there is a difference between the vertical strokes
of the right and left wheels.
[0006] In particular, when a vehicle body is subjected to rolling,
the anti-roll bar functions as an auxiliary spring for causing
spring action in response to the difference between the vertical
strokes of the right and left wheels and is used to control
steering characteristics since it can reduce the rolling and change
the rolling stiffness of the right and left wheels.
[0007] That is, an anti-roll bar functions in such a manner that
the degree of understeer is increased if the stiffness of a front
anti-roll bar is increased while the degree of understeer is
decreased if the stiffness of a rear anti-roll bar is
increased.
[0008] FIG. 1 is a front view of a related art vehicle suspension
system.
[0009] As shown in FIG. 1, a related art vehicle suspension system
20 absorbs vibration or shock transmitted to a vehicle body through
tires at both sides thereof. In particular, lower arms 21, which
are elements of the suspension system 20, are connected to the
tires, respectively, and the both lower arms 21 are interconnected
with each other through an anti-roll bar 10.
[0010] Therefore, the anti-roll bar 10 can reduce the rolling
occurring when the vehicle travels along a curved road.
[0011] However, since the related art anti-roll bar for vehicle is
designed and used to exhibit constant stiffness, the stiffness of
the anti-roll bar cannot be changed in accordance with rapidly
changing vehicle driving conditions such as vehicle speed and
steering angle. Thus, there is a problem in that the driving
comfort or stability can be deteriorated due to the anti-roll bar
with constant stiffness
SUMMARY OF THE INVENTION
[0012] The present invention is conceived to solve the
aforementioned problem in the prior art. An object of the present
invention is to provide a vehicle suspension system wherein
electric power applied to piezoelectric ceramics of an anti-roll
bar of a vehicle can be adjusted in accordance with vehicle driving
conditions such as vehicle speed and steering angle to allow the
anti-roll bar to be controlled to exhibit its optimum stiffness
according to the vehicle driving conditions such that the driving
stability and product value of the vehicle can be maximized.
[0013] According to an aspect of the present invention, there is
provided an apparatus for controlling stiffness of an anti-roll
bar, comprising an anti-roll bar which includes piezoelectric
ceramics and interconnects both lower arms of a vehicle suspension
system, a power converter which is connected to a power supply to
allow electric power to be increased or decreased and to supply
electric power to the piezoelectric ceramics of the anti-roll bar,
and a controller which is connected to the power converter to
calculate electric power needed for providing the piezoelectric
ceramics with optimal stiffness based on previously stored vehicle
speed and steering angle in response to data detected by a vehicle
speed sensor and a steering angle sensor and to control the power
converter such that the calculated power can be supplied to the
piezoelectric ceramics.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other objects, features and advantages of the
present invention will become apparent from the following
description of preferred embodiments in conjunction with the
accompanying drawings, in which:
[0015] FIG. 1 is a front view of a related art vehicle suspension
system;
[0016] FIG. 2 is a front view schematically showing the
configuration of an apparatus for controlling stiffness of an
anti-roll bar for a vehicle according to the present invention;
and
[0017] FIG. 3 is a sectional view taken along line A-A of FIG.
2.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Hereinafter, a preferred embodiment of the present invention
will be described in detail with reference to the accompanying
drawings.
[0019] FIG. 2 is a front view schematically showing the
configuration of an apparatus for controlling stiffness of an
anti-roll bar for a vehicle according to the present invention, and
FIG. 3 is a sectional view taken along line A-A of FIG. 2.
[0020] As shown in FIGS. 2 and 3, the apparatus for controlling
stiffness of an anti-roll bar for a vehicle is characterized by
comprises an anti-roll bar 100 which includes piezoelectric
ceramics 110 and interconnects both lower arms 410 of a vehicle
suspension system 400, a power converter 200 which is connected to
a power supply 500 to allow electric power to be increased or
decreased and to supply electric power to the piezoelectric
ceramics 110 of the anti-roll bar 100, and a controller 300 which
is connected to the power converter 200 to calculate electric power
needed for providing the piezoelectric ceramics 110 with optimal
stiffness based on previously stored vehicle speed and steering
angle in response to data detected by a vehicle speed sensor 600
and a steering angle sensor 700 and to control the power converter
200 such that the calculated power can be supplied to the
piezoelectric ceramics 110.
[0021] Hereinafter, the operation of the present invention will be
described with reference to FIGS. 2 and 3.
[0022] As shown in FIG. 2, the apparatus for controlling stiffness
of the anti-roll bar according to the present invention so
configured is the same as that of the related art in view of their
installation positions, but the present invention is different from
the related art in that the anti-roll bar 100 of the present
invention includes the piezoelectric ceramics 110 and can control
the supply of electric power such that the anti-roll bar 100
including the piezoelectric ceramics 110 exhibits predetermined
stiffness suitable for the driving conditions.
[0023] At this time, the anti-roll bar 100 is preferably configured
in such a manner that its outer circumferential surface be enclosed
by the piezoelectric ceramics 110, as shown in FIG. 3.
[0024] In general, when an external force is applied to an ion
crystal in a specific direction, one side thereof is positively
charged and the other is negatively charged due to internal stress
produced therein. Thus, a voltage is created in the crystal. This
phenomenon is called a positive piezoelectric effect. On the other
hand, when an external voltage is applied to a crystal, the crystal
is deformed or distorted. This phenomenon is called a negative
piezoelectric effect.
[0025] That is, according to the piezoelectric effect, a mechanical
force (stress) is converted into an electrical signal (voltage),
and vice versa. A material having such a piezoelectric property is
called piezoelectrics, and such a piezoelectric material made of
ceramics is called piezoelectric ceramics 110.
[0026] Therefore, the aforementioned piezoelectric ceramics 110
uses the principle that when electric power is applied thereto,
stress is created in the piezoelectric ceramics 110 and the
stiffness of the piezoelectric ceramics 110 is changed accordingly.
For example, the stiffness of the piezoelectric ceramics 110 is
increased when large electric power is applied thereto, while the
stiffness is decreased when relatively small electric power is
applied thereto.
[0027] As shown in FIG. 2, the piezoelectric ceramics 110 is also
connected to the power converter 200 for increasing or decreasing
the power supplied from the power supply 500 such as a battery in
the vehicle, and the power converted 200 is controlled by the
controller 300.
[0028] That is, the magnitude of electric power supplied to the
piezoelectric ceramics 110 can be controlled under the control of
the controller 300.
[0029] Further, the controller 300 is connected to the vehicle
speed sensor 600 for measuring vehicle speed and transmitting the
detected vehicle speed to the controller in the form of a
corresponding electrical signal, and the steering angle sensor 700
for measuring a steering angle made by a driver and transmitting
the detected steering angle to the controller in the form of a
corresponding electrical signal.
[0030] Furthermore, data on the optimal stiffness that the
anti-roll bar 100 should exhibit in response to the detected
vehicle speed and steering angle are beforehand stored in the
controller 300, and data on the electric power that should be
accordingly supplied to the piezoelectric ceramics 110 of the
anti-roll bar 100 are also beforehand stored.
[0031] Therefore, the controller 300 can control the power
converter 200 such that the piezoelectric ceramics 110 of the
anti-roll bar 100 can exhibit the optimal stiffness in response to
a current vehicle speed detected by the vehicle speed sensor 600
and a current steering angle detected by the steering angle sensor
700. Then, suitable electric power can be supplied to the anti-roll
bar 100, and consequently, the anti-roll bar 100 can exhibit
optimal stiffness corresponding to current driving conditions.
[0032] At this time, it is preferred that the power converter 200
can increase or decrease the voltage supplied to the piezoelectric
ceramics 110.
[0033] Therefore, since the apparatus for controlling stiffness of
an anti-roll bar for a vehicle according to the present invention
can actively change the stiffness of the anti-roll bar 100 suitably
in accordance with the vehicle speed and steering angle, the
anti-roll bar 100 can exhibit stiffness suitable for the vehicle
driving conditions. Thus, there is an advantage in that both the
driving stability and product value of vehicle can be greatly
enhanced.
[0034] According to the present invention so configured, the
vehicle speed and steering angle can be adjusted in accordance with
the electrical power supplied to the piezoelectric ceramics of the
anti-roll bar such that the anti-roll bar can be controlled to
exhibit optimal stiffness suitable for the driving conditions.
Therefore, the driving stability and product value of vehicle can
be maximized.
* * * * *